InfoSci®-Journals Annual Subscription Price for New Customers: As Low As US$ 4,950

This collection of over 175 e-journals offers unlimited access to highly-cited, forward-thinking content in full-text PDF and XML with no DRM. There are no platform or maintenance fees and a guarantee of no more than 5% increase annually.

Receive the complimentary e-books for the first, second, and third editions with the purchase of the Encyclopedia of Information Science and Technology, Fourth Edition e-book. Plus, take 20% off when purchasing directly through IGI Global's Online Bookstore.

Take 20% Off All Publications Purchased Directly Through the IGI Global Online Bookstore: www.igi-global.com/

Abstract

This chapter examines the capability of Genetic Programming (GP) and different Artificial Neural Network (ANN) (Backpropagation [BP] and Generalized Regression Neural Network [GRNN]) models for prediction of air entrainment rate (QA) of triangular sharp-crested weir. The basic principal of GP has been taken from the concept of Genetic Algorithm (GA). Discharge (Q), drop height (h), and angle in triangular sharp-crested weir (?) are considered as inputs of BP, GRNN, and GP. Coefficient of Correlation (R) has been used to assess the performance of developed GP, BP, and GRNN models. For a perfect model, the value of R should be close to one. A sensitivity analysis has been carried out to determine the effect of each input parameter. This chapter presents a comparative study between the developed BP, GRNN, and GP models.

Introduction

A weir is designed to change flow characteristics of river. Different shapes of weir are used such as rectangular weir, triangular or v-notch weir, the broad-crested weir, etc. The amount of dissolved oxygen in a river system is increased by weir. The change in oxygen concentration due to weir is given by the following equation

(1) where dm/dt is mass transfer rate of gas molecules across an interface, Cs and C are the saturation concentration of oxygen in water at prevailing ambient conditions and the actual concentration of oxygen in the water at time t-difference being proportional to the concentration gradient, kL is bulk liquid film coefficient, A is the air–water contact area and V is the volume of water associated with this. Ervine, et al. (1980) explained air entrainment mechanisms by weirs. They gave four mechanism of air entrainment.